Applicable Systems
EFC
FEX
FEI
HNC
Symptoms
The drive trips. The error display shows E-1003, indicating drive overtemperature. The internal heatsink temperature has exceeded the safe operating limit.
Possible Causes
- Drive cooling fan failed or airflow blocked
- Ambient temperature exceeds drive rating
- Drive enclosure ventilation inadequate
- Drive operating at high load for extended period
Troubleshooting Steps
- Step 1: Check the drive cooling fan for operation
Fan is running and airflow is unobstructed - Step 2: Measure the ambient temperature inside the enclosure
Ambient temperature is within the drive rated range - Step 3: Inspect the heatsink fins for dust or debris
Heatsink is clean and air flows freely - Step 4: Improve enclosure ventilation or reduce drive load
Drive temperature stays within safe limits under all conditions
How to Reset
To reset: 1) Allow the drive to cool down. 2) Fix the cooling issue (replace fan, clean heatsink, improve ventilation). 3) Clear the fault. Caution: Repeated overtemperature trips permanently damage the drive power components.
Frequently Asked Questions
- Q: How do I clean a Rexroth drive heatsink?
Power down the drive and wait for capacitors to fully discharge. Use low-pressure compressed air to remove dust from heatsink fins. Do not use liquids or solvents.
- Q: What is the maximum ambient temperature for Rexroth drives?
Most Rexroth EFC drives are rated for ambient temperatures up to +40 or +50 deg C. Above this, output derating is required. Check the drive manual for the specific model's temperature rating.
Source: Bosch Rexroth EFC Drive Manual, 2023
Category: PLC & VFD